Lifting device



2 shees-sneex 1 //V VE /V TOR. //V 1/. l. H0 TT l. VON K. HOTT LIFTINGDEVICE Filed Jan. 5, 1927 TTFPNEY Dec. 30, 1930.

Dec. 30, 1930. l. VON K. HOTT LIFTING DEVICE Filed Jan. 3, 1927 2Sheets-Sheet 2 ATTOR/VE Y l XA su" im Patented Dec. 30, 1930 PATENTorrilce UNITEDY STATES ION VON KERT HOTT, OF DAYTON,`OHIO, ASSIGNOR T0THE JOYCE-CRIDLAND COMPANY, OFDAYTON, OHIG, A CORPORATION OF OHIOrLIFTING DEVICE Application filed January 3, 1927. Serial No. 158,639.

This invention relates to lifting devices and more particularly to apawl and ratchet )ack of the type shown in the application for patenttiled by Hott and Spear on February 2,'

` pawls to control their positions with relation to the toothed element.

The object of the present invention is to provide in such a jack meanswhereby both pawls may be moved to their inoperative positions to permitthe lifting elementto move quickly to its lowermost position.

A further object of the invention is to provide such a device which willbe very simple in its construction and operation and which will be ofsuch a character and so arranged that it will not in any way interferewith the operation or handling of the jack.

Other objects of the invention will appear as the device is described indetail.

In the accompanying drawings Fig. 1 is a side elevation, partly brokenaway, ot a litting jack embodying my invention; F ig. 2 is a verticalsectional view ot sucha ach, partly broken away; F ig. 3 is a sideelevation orP the upper portion of the jack, partly broken away to showthe lifting pawl in its elevated position; and Fig. l is a similar viewshowing the tripping device in its operative position.

In these drawings l Vhave illustrated one A embodiment of my inventionand have shown the same as comprising a base 1 on which is mounted avertical standard 2 having a guideway in which is slidably mounted atoothed element 3. ln the present instance, l have shown the inventionas applied to a pole jaclr andV the upper end ot the lifting element isclaw shaped, as is customary in such jacks, and the standard 2 ispivotally mounted at 4 on the base and is held normally in its uprightposition by means ot' a latch 5 having an actuating arm 6.

Pivotally mounted on the standard 2, in front of the toothed element 3,is a pawlcarrier which is here shown` as comprising a trunnion 7 havingan enlarged portion 8 and provided with means for actuating the same,such as a lever socket 9 to receive the usual operating bar or lever. Alifting pa-wl 10 is pivotally mounted on the pawl carrier at 11, thepoint ot connection of the pawl with the pawl carrier, or enlargedportion of the trunnion7 being spaced some distance from the axis of thetrunnion so that the movement of the latter will impart bodily movementto the pawl. This pawl has secured thereto and preferably formedintegral therewith an apertured lug 12 which extends rearwardly andlaterally therefrom. Pivotally mounted on the standard 2 above thetrunnion 7 is a detent pawl 13 which is, also provided with a rearwardlyand laterally extending apertured lug le. The lugs 12 and 1a arearranged with their apertures in alinement and a rod 15 is slidablymounted in said apertures. This rod has at its upper and lower endsstops 16 and 17 and at a point between its ends it is provided with astop 18. The stop 17 is located below and adapted to engage theapertured lug 12 ot the lifting pawl and the intermediate stop 18 islocated below and adapted to engage the apertured lug 11i of the detentpawl. A spring 19 is confined between the apertured lug 12 or" thelifting pawl and the intermediate stop 18 and a spring 2O is confinedbetween the apertured lug 14 ot the detent pawl and the upper stop 16.Means are provided for depressing the rod 15 and holding the same in adepressed position during the lifting operation and this means is hereshown as comprising a pivoted plate 21 adapted to engage the upper endoi the rod 15 and this plate is actuated by a finger 22 connected wth apivoted operating handle 23. lWhen the rod is held in its depressedpos.: ion the springs 19 and 2O will be under compression and wilL tendto hold the pawls in engage ment withVr the toothed element. 17V hen thepawl carrier is operated to impart upward movement to the lifting pawlthev lifting element will be moved upwardly, the detentypa-wl yieldingto permit the teeth of the toothed element to ride past the same, andwhen'the pawl carrier is moved downwardly the detent pawl will hold thetoothed element against downward movement and the lifting pawl willyield and ride over the teeth of the toothed element, thus permittingthe load to be elevated step by step. lVhen it is desired to lower theload the locking plate 2l released and the springs will move the rodinto the position shown in Fig. l. As there shown, the detent pawl is inengagement with the toothed element andthe lifting pawl has been movedout of engi` gement th with by the contact ot' the lower stop li' n t ithe apertured lug l2. l/Yhen the "awl carrier is artuated to move thelifting pa wl upwardly this pawl will more relatively to the toothedelement but it moves iipw'ai."ly the spring 19 will be placed undercompression and will rock the pawl about its individual axis ll to causethe nose their-zotl to engage the toothed element, the rod tilting topermit of the move'- nient of the pawl. The movement is so timed thatthe lifting pawl will engage the toothed element just before the pawlcompletes its upward movement and the final movement ot' the pawl willimpart a slight upward nievement to the toothed element, therebyreleasing the detent pawl and permitting the saine to be moved to itsinoperativeposition by the action of the spring i9 and stop 18 on thelug la of the detent pawl. The load is then carried by the lifting pawland as the pressure on the operating handle is relieved the load willmove downwardly. As the toothed element and lifting pawl move downwardlytrie lug l2 of the lifting pawl will engage the lower stop 17 on the rodand canse the rod to move -f downwardly, thereby causing the detent pawlto be moved toward the lifting element. This movement is so timed thatthe detent pawl will not engage the lifting element until one or moreteeth of the toothed element have passed the pawl but it will engage thelitting element and support the load just before the lifting pawlreaches its lowerinost position. The final downward movement ot thelifting pawl Vwill cause the lug l2 thereon to engage the lower stop 17which will roch the pawl about its anis and move it out ot engagementwith 'he toothed element. 'By repetition oit this eycle ol operationsthe lead may be lowered step by step.

The mechanism and operation above described enable the load to be raisedand low-f ered step by step but it is sometimes desirable to lower theload quicklyj th at is, to permit the lifting element to move qui l;lowermost position. To accomplish this l have provided means wherebysaid pa wls may be moved to their inoperative positions7 therebyreleasing the toothed element and permitting of the free downwardmovement thereof, either with or without load. In the presentconstruction, the standard 2 ha s' termed therein a vert-ical guidewayQ4 in whieh is slidab'ly mounted a tripping member 25, which is hereshown in the orm of a bar or pl nger, the' upper end of which isarranged in line with and adapted to engage the lower end o'lz the rodl5. Preferably the upper end ol the trippinw plunger has an enlargedhead 26 to provide it with sufiieient area to contact with the end olthe rod when the latter is in either its true vertical position or itstilted position. The lower end of the plunger has a laterally extendingportion or foot 27 which is adapted to be engaged by an actuating cam 28pivotally mounted at 29 on the standard Q. Connected with the cam is anoperating nunnber7 here shown in the form of a handle l() and soarranged that when the cam is in its inoperative position the handlewill extend alongside ot' the standard and close thereto. The cam 28 isso shaped that when the handle is moved outwardly7 and upwardly the can:will force the plunger upwardly and thus cause it to contact with therod l5 and move that rod upwardly. The nose 3l ol the cani so arrangedthat when the cam isl in its uppermost or fully operative position thepoint ol contact between the plunger and the cam will be offset orarranged on the outer side olA the axis of the cam so that when the camis released the pressure of the plnng r thereon will restore the cam toits inopeative position, thereby preventing the cam from beinginadvertently left in a position which would render the mechanisminopeative.

lVhen the lool-:ing plate 2l released and the operating lever 9' is inits lowermost position the lifting pawl will be in engagement with thetoothed element and the detent pawl will be in its inoperative position.lf the litting pawl has sullicient movement with relation to the pawlsupporting member S the rod l5 m-ay be moved far enough to torce thispawl out of engagement with the toothed element, but where, as in thepresent instance. the movement of the pawl is limited the npwardmovementot the rod will not force the Apawl to its inoperative positionbut the tripping member will hold the rod in its elevated position sothat. the downward movement of the pawl, when the operating lever iselevated, will canse the lug l2 on the lifting pawl to engage the lowerstop 1T on the rod. thus rocking the pawl about its axis to aninoperative position and releasing the toothed element.

lllhen the operating lever is in its raised position the lifting pawl.will he in its ii'ioperative position and the datent pa wl in itsoperative position, and the upward movement im. parted to the rod bythev tripping device will force' the detent pawl out olf' engagementwith the toothed element.

The actuating device 'li'or the plunger may be of any suitable characterbut, i n the p r'e sont instance, I have utilized 'for this purpose oneof two carrying handles 30 which are pivotally mounted on the oppositesi Tes et the standard 2 and are provided with s aces 32 arranged to?Contact with the sides' ot the' weaves standard and forni stops to limitthe upward movement of the handles. One of the carrying handles isarranged beneath the plunger 25 and in order to utilize the saine as anactuating device for the plunger I have shaped the upper end thereof,beyond the surface 32, to provide the cam 28, which will en gage antactuate the plunger when the handle is moved to its extended position.

While I have shown and described one embodiment of my invention I Wishit to be understood that I do not desire to be limited to the detailsthereof as various modifications may occur to a perso-n skilled in theart.

Having now fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

l. In a lifting device, a standard, a toothed element carried by saidstandard, a lifting paivl and a detent paWl supported on said standardand cooperating with said toothed element, means to actuate said liftingpa-Wl, a rod connected With and capable of longitudinal movement vvithrelation to said paivls, springs carried by said rod and acting on saidpavvls, means to control the longitudinal movement of said rod andthereby control the operation of said paivls, and other means to controlthe longitudinal movement of said rod to cause both of said paWls toassume inoperative positions with relation to said toothed element. V

2. In a lifting device, a standard, a toothed element carried by saidstandard, a lifting pavvl and a detentk paWl cooperating with saidtoothed element, means to actuate said lifting pawl, a rod connectedwith and capable of longitudinal movement With relation to said pa-Wls,springs carried by said rod and acting on said pavvls, means to controlthe longitudinal movement of said rod and thereby control the operationsof said pawls, a tripping device to act on said rod to cause said paWlsto be moved into inoperative positions, and means for actu ating saidtripping device.

In a lifting device, a standard. a toothed clement carried by saidstandar-fl, a lifting paavl and a detent paivl cooperating with saidtoothed element, means to actuate said lifting pawl, a rod connectedwith and capable of longitudinal movement with relation to said pavvls,springs carried by said rod and acting on said paivls, a tripping deviceslidably mounted on said standard and arranged to engage said rod, andmeans for imparting sliding movement to said trip ping device.

ll, In a lifting device, a standard, a toothed elementcarried by saidstandard, a lifting paivl and a detent pavvl cooperating With saidtoothed element, means to actuate said lifting pavvl, a rod connectedwith and capable of longitudinal movement With relation to said pawls,springs carried by said rod and acting on said pavvls, a tripping deviceslidably mounted on said standard and arranged to engage said rod, a camacting on said tripping device to impart sliding movement thereto, andmeans for actuating said cam.

5. In a lifting device, a standard, a toothed element carried by saidstandard, a lifting paWl and a detent paivl cooperating with saidtoothed element, means to actuate said lifting pavvl, a rod connectedwith and capablo of longitudinal movement with relation to said pawls,springs carried by said rod and acting on said pawls, a plunger slidablymounted on said standard, a cam pivotally mounted on said standardbeneath said plunger and having a. contact portion offset from the axlethereof, and a handle operatively connected with said cam.

6. In a-lifting device, a standard, a toothed element carried by saidstandard, a lifting pawl and a detent paivl cooperating With saidtoothed element, means to actuate said lifting patvl, a. rod connectedwith and capable of longitudinal movement with relation to said pawls,springs carried by said rod and acting on said paWls, means for movingsaid rod in one direction to cause both paivls to be moved intooperative relation to said toothed element, and means for moving saidrod in the opposite direction to permit both pawls to be moved intoinoperative positions with relation to said toothed element.

7 In a lifting device, a standard, a toothed element carried by saidstandard, a lifting pawl and a detent pavvl supported on said standardand cooperating With said toothed element, means for actuating saidlifting paivl,'and means for controlling the positions of said pavvlswith relation to said toothed element, said means comprising springsacting on said pawls, a rod having longitudinal movement with relationto both pavvls, means to limit the movement of said rod in one directionto cause both pavvls to operatively engage said toothed element, andmeans movable into and out of a position to limit the movement of saidrod in the other direction and thus cause both pawls to be moved intoinoperative positions with relation to said toothed element.

In testimony whereof, I affix my signature hereto.

IOl\T VON KER-T HOTT.

